1. Field of the Invention
This invention relates to electronic computers and network systems, and more particularly to a network server for automatically decompressing selected pre-compressed data streams and recompressing the decompressed data to a greater degree than the original pre-compressed data.
2. Description of Related Art
FIG. 1 is a diagram of a prior art wide area public network system, such as the Internet. A first node 2 (which may be a workstation, a terminal, a personal computer, or the like), can communicate with a second node 4 (which may be a network server, a minicomputer or mainframe computer, a personal computer, or the like) by an apparently direct connection 6. In reality, the connection between node 2 and node 4 is made through a network "cloud" of connections 8, generally through one or more "proxy" server computers 10 that help route requests through the network 8. Such proxy server computers 10 generally include storage devices 12 for storing various sorts of data.
Each connection between a pair of nodes 2, 4 consumes some amount of communication bandwidth. In order to conserve bandwidth, it is common to pre-compress files to be transmitted from one node 2 to another 4. For example, graphics images may be pre-compressed using commonly available file formats, such as the Graphics Interchange Format (GIF), Tagged Interchange File Format (TIFF), and JPEG. (It should be understood that the term "files" as used herein includes live data streams, collections or archives of files, portions of files, data blocks, etc.)
One drawback of the present system is that such pre-compressed files may not be optimally compressed, thus wasting bandwidth. However, a requester node 2 generally has no ability to cause a provider node 4 to optimize compression of requested files.
Another existing problem is that many files on provider nodes 4 are not pre-compressed at all. While some compression may be achieved automatically by use of transport protocols or modems that include a compression function, there is no general solution to this problem.
The present invention is based on the inventor's recognition of a need for optimizing bandwidth usage in a network system for pre-compressed data files, and a need for general method of compressing files that are not pre-compressed.
The present invention provides a solution to these problems.